Thad,

IPC-D-275, Para 5.3.1.4 Edge Spacing - states that "except for edge-board
contacts, the minimum distance between conductive surfaces and the edge of
the finished board shall not be less than teh minimum electrical spacing
requirements plus 0.016in."

Para 5.4.4 states that "the spacing between adjacent, non-land holes, shall
be not less than the finished board thickness or the hole diameter, whichever
is less."

Regards,

Gary Ferrari
Tech Circuits
(203)269-3311
Chairman - IPC-D-275 committee